Shutter luminous fibres based on rare-earth materials for real-time thermal response

Abstract

Rare earth luminescent materials (RELMs) are commonly used in optics and products intended for safety and decoration. However, there is still a great challenge to alternate the emission performance after the RELMs are activated. In this work, a novel shutter luminous fibre (SLF) was developed using a water-spin method with polyacrylonitrile (PAN) as the filament material. The emission performance of the RELMs SLFs could be alternated at near-ambient temperatures. A heat-sensitive thermochromic pigment composed mainly of 7-Anilino-3-diethylamino-6-methyl fluoran (TF-BL1) served as the shutter material. The emitting properties, shielding effect, and the temperature response behaviour of RELMs SLFs with primary colour-emitting properties (Sr2ZnSi2O7: Eu2+, Dy3+; SrAl2O4: Eu2+, Dy3+; and Y2O2S: Eu3+, Mg2+, Ti4+) were investigated. The quinoid structure of TF-BL1 blocked the light of primary colours at low temperatures. At high temperatures, the lactone structure of TF-BL1 allowed the light of the RELMs to emit. SLFs with real-time responding behaviour have great potential as electronic skin in soft robotics, flexible electronics, and camouflage applications.